m.youtube.com is for regular cell phones and uses 3GP videos not compatible with iPhone. What happened to your YouTube app?
Home: 2006.5 iMac 20"
Me: 2010 MacBook Pro 13", iPad Mini Wifi 32GB Black, iPhone 4 16GB Black
Wife: 2011 MacBook Air 11.6", iPhone 4 16GB White
Are you backed up??? If so, why? Psyllium Fibre is not free but will do wonders!